High voltage windings are used in various applications such as in transformers, DC motors and electrical inductors. Large energies are stored in such windings in the form of a magnetic field. Because of the large stored energy, testing of these windings is difficult and frequently hazardous. For example, it is desirable to test a high voltage power transformer such as used in an electric power station during installation and before it is placed in operation. This helps ensure that the transformer will operate properly. Shipping damage and manufacturing defects can sometimes be found with a DC resistance test. Appropriate electrical meters are typically connected to leads on the winding and a DC voltage is applied to the winding. Because of the winding's inductance, several minutes are required for the current to stabilize at a constant value. After voltage and current readings are taken, the DC voltage source is shut-down leaving residual energy stored in the magnetic field of the winding. The residual energy should be allowed to dissipate prior to complete removal of the battery from the winding for safety reasons and to protect test equipment. Typically, the meters are disconnected from the winding before the magnetic field is dissipated. When the battery is disconnected, an arc on the order of 3-4 inches is produced. This is not only extremely hazardous to the worker testing the winding, but sometimes results in damage to or destruction of the metering devices.